74F257ASCX Equivalent & Substitute Parts

Part Overview

The 74F257ASCX is a 4 x 2:1 multiplexer logic integrated circuit manufactured by onsemi in a 16-SOIC surface mount package. This component functions as a data selector, routing one of four input signals to a single output based on control logic. The part is classified as obsolete, making equivalent substitute components necessary for new designs and ongoing production support.

Substiute Parts

74F257ASCX

onsemiIn Stock: 1853074F257ASCX Datasheet

Current PartRFQ

SN74F257D

Texas InstrumentsIn Stock: 2044SN74F257D Datasheet

SimilarRFQ

SN74F257DR

Texas InstrumentsIn Stock: 5337SN74F257DR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 74F257ASCX is determined by strict equivalence across the following parameters:

• Circuit configuration: 4 x 2:1 multiplexer topology
• Independent circuits: 1 unit
• Output current specifications: 3mA high, 24mA low
• Supply voltage: 4.5V ~ 5.5V single supply
• Operating temperature: 0°C ~ 70°C
• Package: 16-SOIC form factor with 0.154" width (3.90mm)
• Mounting: Surface mount technology

All identified substitutes maintain identical electrical and mechanical parameters, ensuring direct functional replacement without circuit redesign.

Parameter Comparison

Engineering Selection Recommendations

SN74F257DR (Texas Instruments) is the primary recommended substitute. This part maintains active product status, ensuring long-term availability and supply chain stability. It carries ROHS3 compliance certification and is supplied in Tape & Reel format, supporting automated assembly processes. All electrical and mechanical parameters are identical to the 74F257ASCX.

SN74F257D (Texas Instruments) serves as a secondary option. While functionally equivalent across all electrical specifications, this part is classified as Last Time Buy, indicating limited future availability. It is supplied in Tube packaging, suitable for manual assembly or lower-volume applications.

The onsemi 74F257ASCX, classified as obsolete, should be replaced in new designs. Both Texas Instruments alternatives provide equivalent performance with improved product lifecycle status and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can SN74F257DR directly replace 74F257ASCX in existing designs? A: Yes. The SN74F257DR is a parametric equivalent with identical circuit configuration, output current ratings, supply voltage range, operating temperature, and 16-SOIC package dimensions. No circuit modifications are required.

Q: What is the difference between SN74F257D and SN74F257DR? A: Both parts are electrically identical. The primary difference is packaging format: SN74F257D is supplied in Tube, while SN74F257DR is supplied in Tape & Reel (TR). The TR format is optimized for automated pick-and-place assembly. Product status also differs: SN74F257D is Last Time Buy, while SN74F257DR is Active.

Q: Are there any compliance differences between the substitutes? A: Both Texas Instruments parts are ROHS3 compliant and REACH unaffected. The onsemi 74F257ASCX does not specify RoHS status. All three parts have MSL rating of 1 (Unlimited) and identical ECCN and HTSUS classifications.

Q: Which substitute should be selected for new production? A: SN74F257DR is recommended for new designs due to active product status, ensuring availability throughout the product lifecycle. Its Tape & Reel packaging supports high-volume automated manufacturing.

Q: Is the 16-SOIC package footprint identical across all three parts? A: Yes. All three parts use the 16-SOIC package with 0.154" width (3.90mm). PCB layouts and footprints are directly compatible without modification.